From fb2fc4cf555e1a5eb4f061ca7c76adf667407f9c Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Sun, 2 Dec 2007 13:18:39 +0200 Subject: KVM: x86 emulator: fix access registers for instructions with ModR/M byte and Mod = 3 patch 4e62417bf317504c0b85e0d7abd236f334f54eaf in mainline. The patch belows changes the access type to register from memory for instructions that are declared as SrcMem or DstMem, but have a ModR/M byte with Mod = 3. It fixes (at least) the lmsw and smsw instructions on an AMD64 CPU, which are needed for FreeBSD. Signed-off-by: Aurelien Jarno Signed-off-by: Avi Kivity Signed-off-by: Greg Kroah-Hartman --- drivers/kvm/x86_emulate.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c index 804e86c57c60..08cd4a385c06 100644 --- a/drivers/kvm/x86_emulate.c +++ b/drivers/kvm/x86_emulate.c @@ -773,6 +773,14 @@ done_prefixes: case SrcMem: src.bytes = (d & ByteOp) ? 1 : op_bytes; srcmem_common: + /* + * For instructions with a ModR/M byte, switch to register + * access if Mod = 3. + */ + if ((d & ModRM) && modrm_mod == 3) { + src.type = OP_REG; + break; + } src.type = OP_MEM; src.ptr = (unsigned long *)cr2; if ((rc = ops->read_emulated((unsigned long)src.ptr, @@ -839,6 +847,15 @@ done_prefixes: dst.type = OP_MEM; dst.ptr = (unsigned long *)cr2; dst.bytes = (d & ByteOp) ? 1 : op_bytes; + dst.val = 0; + /* + * For instructions with a ModR/M byte, switch to register + * access if Mod = 3. + */ + if ((d & ModRM) && modrm_mod == 3) { + dst.type = OP_REG; + break; + } if (d & BitOp) { unsigned long mask = ~(dst.bytes * 8 - 1); -- cgit v1.2.3